Hip prostheses for replacement of damaged or diseased human hips have long been known in the art. Heretofore, such prosthetic devices have typically included an acetabular component providing an artificial acetabulum, and a femoral component including a femoral stem for implanting in the femur and a neck portion carrying a head for being rotatably received in the artificial acetabulum. Examples of such devices are disclosed in U.S. Pat. Nos. 3,906,550; 4,365,358; 4,514,865; 4,676,797; and 4,714,471, and in European Patent No. 0000549. Generally, the femoral stem of such devices comprises a proximal portion for implantation in the proximal femur and a distal portion which is closely received in the medullary canal so as to extend into the diaphysis or shaft of the femur. The distal portion of the stem serves primarily to stabilize the proximal portion of the stem such that overall stability of the component may ensue. However, the implantation of the distal stem into the medullary canal can result in post operative pain due to stress risers that may occur at the prosthesis-bone interface. Further, the infinite variety of shapes, sizes and contours of the femur preclude precise press-fit relationships between prosthesis and bone when intramedullary stems are used. Also, the reaming of the femur necessary for the implantation of the distal stem can undermine the strength of the femur, and later removal of the distal stem should the prosthesis require replacement can be difficult and damaging to the surrounding bone structures. Moreover, the intramedullary dimensions of the femur tend to expand with aging, potentially producing loosening and pain at the distal stem region.
Therefore, it is an object of the present invention to provide a femoral component for a hip prosthesis which does not require the implantation of a distal stem in the medullary canal.
It is another object of the present invention to provide a femoral component for a hip prosthesis which is easily implanted and secured in the desired position.
Yet another object of the present invention is to provide a femoral component for a hip prosthesis which minimizes post operative pain.
Still another object of the present invention is to provide a femoral component for a hip prosthesis which minimizes structural damage to the femur upon implantation and upon later revision of the prosthesis should that become necessary.